Add lemon juice to the roasting pan used to make Lemon-Herb Roasted Chicken set across 2 stovetop burners over medium-high heat. Bring juices to a boil and simmer, scraping up browned bits from bottom and sides of pan with a wooden spoon. Pour mixture into a gravy separator; slowly pour the juices back into the roasting pan and discard the fat remaining in the separator.

Add another chicken broth to pan and simmer until the pan gravy is reduced to about 3/4 cup. Add any accumulated juices from the chicken platter to the gravy with parsley and black pepper.